The statement comes after Trump on Thursday questioned, in bluntly vulgar language, why the US would accept more immigrants from Haiti and "shithole countries" in Africa rather than places like Norway, as he rejected a bipartisan immigration deal, according to people briefed on the extraordinary Oval Office conversation.

The sources spoke on condition of anonymity because they weren't authorised to publicly describe the conversation. One said lawmakers in the room were taken aback by Trump's remarks.

Trump's contemptuous description of an entire continent startled lawmakers in the meeting and immediately revived charges that the president is racist. The White House did not deny his remark but issued a statement saying Trump supports immigration policies that welcome "those who can contribute to our society."

The reference was to the Deferred Action for Childhood Arrivals (DACA) programme, which shields from deportation nearly 800,000 immigrants brought to the country illegally as children.

'Proud son of the shining continent called Africa'

Africans reacted angrily on Friday with many lashing the US president for racism and ignorance.

Social media users across the continent posted images of modern skylines and beautiful nature from their countries with the ironic hashtag "shithole."

Others heaped scorn on a president who last year caused widespread sniggering when he twice referred to Namibia as "Nambia".

"I'm a proud son of the shining continent called Africa. My heritage is deeply rooted in my Kenyan roots. Africa is NO #shithole Mr. Trump," tweeted record-holding Kenyan runner Bernard Lagat, who became a US citizen in 2004.

The United Nations slammed Trump's reported remarks as "shocking and shameful" and "racist".

"You cannot dismiss entire countries and continents as 'shitholes' whose entire populations, who are not white, are therefore not welcome," Rupert Colville, spokesman for the UN human rights office, told reporters in Geneva.

Many reminded the US of its historic role in the continent's woes.

"President Trump, One day, I'll take you to a 'shithole' country called Ghana," wrote Ghanaian Edmond Prime Sarpong on Facebook.

"First stop would be Osu Castle, Elmina Castle, and the over 40 Forts that detained about 30 million slaves, beaten and shipped out like sardine cans and then I will tell you the history of Africa and why people like you made that a 'shithole' continent."

But on Friday, Trump denied he had made such comments.

"The language used by me at the DACA meeting was tough, but this was not the language used," Trump tweeted early on Friday.

He also denied making "derogatory" comments about the people of Haiti, one of several places he was quoted as describing as "shithole countries" in remarks that triggered international outrage.